The present invention is directed to a water filtration system. More particularly, the present invention is directed to a portable water filtration system in which unfiltered and filtered water are stored in chambers separated from one another and in which water flows through a filter having a unidirectional valve that permits flow only from the unfiltered chamber to the filtered chamber.
Filtering and purifying water to make it suitable for drinking have been an on-going challenge throughout the world, particularly in developing countries. Sources of drinking water can be naturally contaminated, as by biological impurities, and/or contaminated by chemical and other non-naturally occurring sources.
Large scale, e.g., land-based purification systems have been developed to address the problem of contaminated water supply. However, access to water thus purified is not always available. To meet the needs of traveling public, several portable water filters and purifiers have been developed. Some of these portable water filters and purifiers are disposed in sports bottles that allow a user to obtain clean drinking water “on the go”.
Several portable water filters and purifiers have been introduced that rely on pressure differential, as developed by suction from the mouth piece and or pressure on the bottle (e.g., squeezing the bottle) for water flow. Other portable systems rely on a straw-like mouth piece through which the water must be drawn. In both of these systems, water is purified as it flows from the container bottom to the top. One principle drawback to these purifiers is that the user must exert a large force (as by sucking action) to draw the water through the purifier. Other portable water purifiers rely on filters and purifiers configured as cartridges that are mounted in the cap of a sports bottle.
In all these systems water is purified as it flows through the cartridge. Granular activated carbon and carbon blocks (with iodinated resin) formed as cartridges that attach bottle caps are also known in the art. In most of these systems, a full squeeze of the container is required to force water to flow through the cartridge. Releasing the pressure from the squeezing action reduces the pressure in the container which can cause water in the cartridge to flow back into the container.
Still another system is a three stage portable water purifier system. Water is purified as it flows from bottom of the container to the top of the container. Although this system functions well, it has a major limitation in that the bottle must be kept in a vertical position while in use. This may be contrary to normal use, in which a user would typically tilt the bottle to obtain a drink.
Yet another system includes a water filter bottle in which the receiving chamber is double walled to separate the inlet and outlet of water. Water to be purified flows by gravity through the filter. However, flow through the filter relies on gravity and is thus quite slow.
Accordingly, there is a need for a multistage water purification device. Desirably, such a device maintains the filtered and unfiltered water separated from one another. More desirably, such a device is configured to induce water flow by manually squeezing a receiving compartment forcing air from the compartment and creating a driving force through lower pressure for water flow for purification.